Printed circuit board and method manufacturing the same

ABSTRACT

A circuit component built-in module of the present invention includes an insulating substrate formed of a mixture comprising 70 wt % to 95 wt % of an inorganic filler and a thermosetting resin, a plurality of wiring patterns formed on at least a principal plane of the insulating substrate, a circuit component arranged in an internal portion of the insulating substrate and electrically connected to the wiring patterns, and an inner via formed in the insulating substrate for electrically connecting the plurality of wiring patterns. Thus, a highly reliable circuit component built-in module having high-density circuit components can be obtained.

[0001] This application is a division of U.S. application Ser. No.09/956,511, filed Sep. 20, 2001, which is a division of Ser. No.09/484,899, filed Jan. 18, 2000, now U.S. Pat. No. 6,338,767 B1, whichis a division of Ser. No. 09/196,792, filed Nov. 20, 1998, now U.S. Pat.No. 6,038,133.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a circuit component built-inmodule. In particular, the present invention relates to a circuitcomponent built-in module in which, for example, an active component isarranged in an internal portion of an insulating substrate.

[0004] 2. Description of the Prior Art

[0005] Recently, with a demand for high performance and miniaturizationof electronic equipment, high-performance and high-density circuitcomponents have been increasingly desired. This leads to a demand for acircuit substrate commensurate with high-performance and high-densitycircuit components.

[0006] The formation of a multilayered circuit may be a solution toachieve higher-density circuit components. However, a conventionalglass-epoxy substrate requires a through-hole structure to form amultilayered circuit, to that is hardly a solution for high-densitymounting. Therefore, a connection method using inner via holes that canconnect between wiring patterns of LSIs or circuit components in theshortest distance has been developed in various fields in order toachieve higher density packaging.

[0007] The connection method using inner via holes allows electricalconnection only between the layers necessary to be connected through aconnection called an inner via, so that circuit components can bemounted with high density (U.S. Pat. No. 5,481,795, U.S. Pat. No.5,484,647, and U.S. Pat. No. 5,652,042)

[0008] However, a substrate that has been conventionally used in theinner via connection comprises a resin based material, which has lowthermal conductivity. Therefore, the problem of a low thermalconductivity is posed. In a circuit component built-in module, thehigher density mounting of circuit components leads to an increaseddemand for releasing heat that has been generated in the components.However, the conventional substrate cannot sufficiently release heat,and therefore, the reliability of the circuit component built-in moduledeteriorates.

SUMMARY OF THE INVENTION

[0009] It is the object of the present invention to provide a highlyreliable circuit component built-in module in which circuit componentsare mounted with high density, and a method for producing the same.

[0010] A first circuit component built-in module of the presentinvention includes an insulating substrate formed of a mixturecomprising 70 wt % to 95 wt % (on the basis of the mixture) of aninorganic filler and a thermosetting resin; a plurality of wiringpatterns formed on at least a principal plane of the insulatingsubstrate (one wiring pattern consists of a group of electric linesformed on the same plane); a circuit component arranged in an internalportion of the insulating substrate and electrically connected to thewiring patterns; and an inner via formed in the insulating substrate forelectrically connecting the plurality of wiring patterns.

[0011] The first circuit component built-in module allows circuitcomponents to be mounted with high density, because the inner via formedin the insulating substrate establishes inner-via-hole connection.

[0012] Furthermore, the first circuit component built-in module allowscircuit components to be mounted with further higher density by mountingcircuit components on the wiring patterns formed in an internal portionof the insulating substrate.

[0013] Furthermore, the first circuit component built-in moduleconstitutes a highly reliable circuit component built-in module, becauseheat generated in the circuit components is released promptly by theinorganic filler.

[0014] Furthermore, the first circuit component built-in module allowsthe heat conductivity, the coefficient of linear expansion, thedielectric constant, the breakdown voltage or the like of the insulatingsubstrate to be changed in accordance with the circuit components byselecting a suitable inorganic filler. When the circuit componentbuilt-in module includes a semiconductor device and a chip capacitor,noise in electric signals can be reduced by reducing the distancebetween the semiconductor device and the chip capacitor.

[0015] In one embodiment of the first circuit component built-in module,the wiring patterns are preferably formed on the principal plane and inan internal portion of the insulating substrate. Mounting circuitcomponents on the wiring patterns formed in an internal portion of theinsulating substrate further increases the density in the circuitcomponents.

[0016] In one embodiment of the first circuit component built-in module,the circuit component preferably includes an active component, and theinner via is preferably formed of a conductive resin composition. Acircuit component having a desired function can be formed by includingan active component in the circuit components. When the inner via isformed of a conductive resin composition, the production of the circuitcomponent built-in module can be facilitated.

[0017] In one embodiment of the first circuit component built-in module,the circuit component is preferably shielded from external air by theinsulating substrate. Shielding circuit components from external airprevents the reliability of the circuit components from deteriorating,which otherwise might deteriorate due to humidity.

[0018] In one embodiment of the first circuit component built-in module,the thermosetting resin preferably comprises at least one thermosettingresin selected from the group consisting of an epoxy resin, a phenolresin and a cyanate resin. These resins are excellent in heat resistanceand electrical insulation.

[0019] In one embodiment of the first circuit component built-in module,the inorganic filler comprises at least one inorganic filler selectedfrom the group consisting of Al₂O₃, MgO, BN, AlN and SiO₂. Use of theseinorganic filler provides an insulating substrate having an excellentheat dissipation. When MgO is used for the inorganic filler, thecoefficient of linear expansion of the insulating substrate can beraised. When SiO₂ (especially, amorphous SiO₂) is used for the inorganicfiller, the dielectric constant of the insulating substrate can bereduced. When BN is used for the inorganic filler, the coefficient oflinear expansion of the insulating substrate can be reduced.

[0020] In one embodiment of the first circuit component built-in module,an average particle diameter of the inorganic filler is preferably 0.1μm to 100 μm.

[0021] In one embodiment of the first circuit component built-in module,the wiring patterns preferably comprise at least one conductivesubstance selected from the group consisting of copper and a conductiveresin composition. Since copper has a small electrical resistance, finewiring patterns can be formed by using copper. Furthermore, electriclines can be formed easily by using a conductive resin composition.

[0022] In one embodiment of the first circuit component built-in module,the wiring patterns preferably comprise lead frames formed by etching orstamping. The metal lead frame has a low electric resistance. Etchingallows the formation of fine wiring patterns. Stamping allows formationof the wiring patterns with simple equipment.

[0023] In one embodiment of the first circuit component built-in module,the circuit component preferably comprises at least one componentselected from the group consisting of a chip resistor, a chip capacitorand a chip inductor. A chip component can be readily buried in theinsulating substrate.

[0024] In one embodiment of the first circuit component built-in module,preferably, the mixture further comprises at least one additive selectedfrom the group consisting of a dispersant, a coloring agent, a couplingagent and a releasing agent. A dispersant serves to disperse theinorganic filler in the thermosetting resin uniformly and sufficiently Acoloring agent serves to color the insulating substrate, so that theheat dissipation of the circuit component built-in module can beimproved. A coupling agent serves to raise the adhesion between thethermosetting resin and the inorganic filler, so that the insulatingproperty of the insulating substrate can be improved. A releasing agentserves to improve the releasing property of the mold and the mixture, sothat the productivity can be raised.

[0025] In one embodiment of the first circuit component built-in module,the insulating substrate preferably has a coefficient of linearexpansion of 8×10⁻⁶/° C. to 20×10⁻⁶/° C. and a heat conductivity of 1w/mK to 10 w/mK. A heat conductivity close to that of a ceramicsubstrate can be obtained, and a substrate having high heat dissipationcan be obtained.

[0026] In one embodiment of the first circuit component built-in module,the active component preferably comprises a semiconductor bare chip, andthe semiconductor bare chip is preferably flip-chip bonded onto thewiring pattern. The flip chip bonding of the semiconductor bare chipallows high density mounting of semiconductor devices.

[0027] In one embodiment of the first circuit component built-in module,the conductive resin composition preferably comprises, as a conductivecomponent, metal particles of at least one metal selected from the groupconsisting of gold, silver, copper and nickel, and an epoxy resin as aresin component. The above-listed metals have low electric resistances,and an epoxy resin is excellent in heat resistance and electricinsulation.

[0028] A first method for producing a circuit component built-in moduleincludes the following steps: processing a mixture comprising 70 wt % to95 wt % (on the basis of the mixture) of an inorganic filler and anuncured thermosetting resin into a first sheet having a through-hole;filling the through-hole with a thermosetting conductive substance so asto form a second sheet having the through-hole filled with thethermosetting conductive substance; mounting a circuit component on awiring pattern portion in a first film; positioning and superimposingthe second sheet on the side of the first film where the circuitcomponent is mounted, and superimposing a second film having a wiringpattern portion on the second sheet, thereby forming a third sheet inwhich the circuit component is buried; and heating the third sheet so asto form a fourth sheet in which the thermosetting resin and theconductive substance are cured.

[0029] According to the first method, the circuit component built-inmodule of the present invention can be produced easily.

[0030] A second method for producing a circuit component built-in moduleof the present invention is directed to a method for producing a circuitcomponent built-in module having a multilayered structure. The secondmethod includes the following steps: processing a mixture comprising 70wt % to 95 wt % (on the basis of the mixture) of an inorganic filler andan uncured thermosetting resin into a first sheet having a through-hole;filling the through-hole with a thermosetting conductive substance so asto form a second sheet having the through-hole filled with thethermosetting conductive substance; forming a wiring pattern on aprincipal plane of a release film and mounting a circuit component onthe wiring pattern; positioning and superimposing the second sheet onthe principal plane of the release film, and pressing the second sheettogether with the release film provided with the circuit component,thereby forming a third sheet in which the circuit component is buried;peeling the release film from the third sheet so as to form a fourthsheet; and positioning and superimposing a plurality of sheets producedin the same manner as the fourth sheet on one another with a filmincluding a wiring pattern portion on top of the plurality of sheets,and pressing and heating the plurality of sheets and the film, therebyforming a fifth sheet having a multilayered structure in which thethermosetting resin and the conductive substance are cured.

[0031] According to the second method, the circuit component built-inmodule having a multilayered structure of the present invention can beproduced easily.

[0032] In one embodiment of the first and second methods for producing acircuit component built-in module, the circuit component preferablycomprises an active component, and the conductive substance comprises aconductive resin composition. A circuit component having a desiredfunction can be formed by including an active component in the circuitcomponents. Furthermore, when the conductive substance comprises aconductive resin composition, it is easy to fill a through-hole with theconductive substance and to cure the conductive substance. Therefore,the production is facilitated.

[0033] In one embodiment of the first and second methods for producing acircuit component built-in module, the first and second films are formedof copper foils, and the method further comprises the step of removingthe copper foil in a portion other than the wiring pattern portions soas to form wiring patterns after the step of forming a sheet in whichthe thermosetting resin and the conductive substance are cured. Thisstep facilitates the formation of the wiring pattern on the principalplane of the insulating substrate

[0034] In one embodiment of the first and second methods for producing acircuit component built-in module, the first and second films are formedof release films on one principal plane of which wiring patterns areformed, and the method further comprises the step of peeling the releasefilms from the sheet, after the step of forming a sheet having thethermosetting resin and the conductive substance cured. This stepfacilitates the formation of the wiring patterns on the principal planeof the insulating substrate.

[0035] In one embodiment of the first and second methods for producing acircuit component built-in module, the method further includes the stepof injecting a sealing resin between the copper foil or the wiringpattern and the circuit component after the step of mounting the circuitcomponent in the copper foil or the wiring pattern. This step preventsgaps from being formed between the circuit component and the wiringpattern, and strengthens the connection between the circuit componentand the wiring pattern.

[0036] In one embodiment of the first and second methods for producing acircuit component built-in module, the thermosetting resin and theconductive substance are preferably heated at 150° C. to 260° C. forcuring. The heating in this range of temperatures can cure thethermosetting resin without causing damage to the circuit component.

[0037] In one embodiment of the first and second methods for producing acircuit component built-in module, the thermosetting resin and theconductive substance are preferably pressed at a pressure of 10 kg/cm²to 200 kg/cm² while being heated for curing. Pressing while heatingprovides a circuit component built-in module having an excellentmechanical strength.

[0038] In one embodiment of the first and second methods for producing acircuit component built-in module, the step of forming the first sheetfurther comprises the step of heating the sheet mixture at a temperaturebelow a cure temperature (e.g., a temperature lower than a cure startingtemperature) of the thermosetting resin, thereby eliminating theadhesion of the sheet mixture after the step of forming the mixture intothe sheet. A subsequent process can be facilitated by eliminating theadhesion of the sheet mixture.

[0039] In one embodiment of the first and second methods for producing acircuit component built-in module, the step of forming the third sheetby burying the circuit component in the second sheet is preferablyperformed at a temperature below a cure temperature of the thermosettingresin. When the step is performed at a temperature below a curetemperature of the thermosetting resin, the thermosetting resin can besoftened without being cured. This embodiment makes it easy to bury thecircuit component in the second sheet, and also makes it to provide asmooth surface to the circuit component built-in module.

[0040] In one embodiment of the first and second methods for producing acircuit component built-in module, the step of mounting the circuitcomponent on the wiring pattern comprises the step of electrically andmechanically connecting the circuit component and the wiring patternwith solder. This embodiment prevents poor connection between thecircuit component and the wiring pattern due to heating that isperformed to cure the thermosetting resin.

[0041] In one embodiment of the first and second methods for producing acircuit component built-in module, the step of mounting the activecomponent on the wiring pattern comprises the step of electricallyconnecting a gold bump of the active component and the wiring patternwith a conductive adhesive. The use of a conductive adhesive preventspoor connection or dislocation of components from occurring at asubsequent step of heating.

[0042] As described above, the circuit component built-in module of thepresent invention employs the insulating substrate comprising a mixtureof an inorganic filler and a thermosetting resin and also utilizes theinner-via-hole connection. This makes it possible to mount circuitcomponents with high density and also allows high heat dissipation.Therefore, the present invention provides a highly reliable circuitcomponent built-in module with circuit components mounted with highdensity.

[0043] Furthermore, it is possible to mount circuit components withhigher density by making the circuit component built-in module of thepresent invention in a multilayered structure.

[0044] Furthermore, in the circuit component built-in module of thepresent invention, the heat conductivity, the coefficient of linearexpansion, the dielectric constant or the like of the insulatingsubstrate can be controlled by selecting a suitable inorganic filler.Therefore, in the circuit component built-in module of the presentinvention, it is possible to equalize substantially the coefficient oflinear expansion of the insulating substrate with that of thesemiconductor device, so that the present invention is preferably usedas a circuit component built-in module in which a semiconductor deviceis built-in. Furthermore, the heat conductivity of the insulatingsubstrate can be improved so that the present invention is preferablyused as a circuit component built-in module in which a component thatrequires heat dissipation such as a semiconductor device is built-in.Furthermore, it is possible to reduce the dielectric constant of theinsulating substrate, so that the present invention is preferably usedas a circuit component built-in module for high frequency circuits.

[0045] According to the methods for producing a circuit componentbuilt-in module of the present invention, the above-described circuitcomponent built-in module can be produced easily.

[0046] Furthermore, according to the methods for producing a circuitcomponent built-in module of the present invention, wiring patterns canbe buried in the insulating substrate by using a release film providedwith the wiring patterns. Therefore, a circuit component built-in modulehaving a smooth surface can be obtained. Thus, when additional circuitcomponents are mounted on the wiring patterns on the surface, a circuitcomponent built-in module having circuit components mounted with higherdensity can be obtained.

[0047] These and other advantages of the present invention will becomeapparent to those skilled in the art upon reading and understanding thefollowing detailed description with reference to the accompanyingfigures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0048]FIG. 1 is a perspective cross-sectional view showing oneembodiment of a circuit component built-in module of the presentinvention.

[0049] FIGS. 2(a) to 2(h) are views showing a process sequence in anembodiment of a method for producing a circuit component built-in moduleof the present invention.

[0050] FIGS. 3(a) to 3(h) are views showing a process sequence in anembodiment of a method for producing a circuit component built-in moduleof the present invention.

[0051]FIG. 4 is a perspective cross-sectional view showing an embodimentof a circuit component built-in module of the present invention.

[0052] FIGS. 5(a) to 5(h) are views showing a process sequence in anembodiment of a method for producing a circuit component built-in moduleof the present invention.

[0053] FIGS. 6(a) to 6(g) are views showing a process sequence in anembodiment of a method for producing a circuit component built-in moduleof the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Hereinafter, the present invention will be described by way ofembodiments with reference to the accompanying drawings.

[0055] Embodiment 1

[0056] One example of a circuit component built-in module of the presentinvention will be described with reference to FIG. 1 of Embodiment 1.FIG. 1 is a perspective cross-sectional view of a circuit componentbuilt-in module 100 of this embodiment.

[0057] Referring to FIG. 1, the circuit component built-in module 100 inEmbodiment 1 includes an insulating substrate 101, wiring patterns 102 aand 102 b formed on one principal plane and the other principal plane ofthe insulating substrate 101, circuit components 103 connected to thewiring pattern 102 b and arranged in the insulating substrate 101, andan inner via 104 for electric connection between the wiring patterns 102a and 102 b.

[0058] The insulating substrate 101 is formed of a mixture comprising aninorganic filler and a thermosetting resin. For the inorganic filler,for example, Al₂O₃, MgO, BN, AlN or SiO₂ can be used. The inorganicfiller is preferably contained in an amount of 70 wt % to 95 wt % on thebasis of the mixture. The average particle diameter of the inorganicfiller is preferably 0.1 μm to 100 μm. Preferable examples of thethermosetting resin include an epoxy resin, a phenol resin or a cyanateresin, which are highly resistant against heat. An epoxy resin is mostpreferable because of its especially high heat resistance. The mixturemay further comprise a dispersant, a coloring agent, a coupling agent ora releasing agent.

[0059] The wiring patterns 102 a and 102 b are formed of an electricallyconductive substance, such as a copper foil or a conductive resincomposition. When a copper foil is used for the wiring pattern, forexample, a copper foil with a thickness of about 18 μm to 35 μm producedby electrolytic plating can be used. The surface of the copper foil thatis in contact with the insulating substrate 101 is preferably made roughso that the adhesion with the insulating substrate 101 can be improved.Furthermore, the copper foil whose surface has been subjected to acoupling treatment or plated with tin, zinc or nickel can be used forbetter adhesion and oxidation resistance. Furthermore, metal lead frameproduced by etching or stamping can be used for the wiring patterns 102a and 102 b.

[0060] The circuit components 103 include, for example, an activecomponent 103 a and a passive component 103 b. A semiconductor devicesuch as a transistor, an IC, and an LSI can be used for the activecomponent 103 a. The semiconductor device may be a semiconductor barechip. A chip resistor, a chip capacitor or a chip inductor can be usedfor the passive component 103 b. The circuit components 103 may notinclude the passive component 103 b.

[0061] The active component 103 a is connected to the wiring pattern 102a by flip chip bonding. The semiconductor bare chips are flip-chipbonded so that circuit components can be mounted with high density.

[0062] The inner via 104 is formed of a conductive substance. Forexample, a conductive resin composition comprising metal particles and athermosetting resin can be used for the inner via 104. Examples of themetal particles include gold, silver, copper and nickel. Gold, silver,copper and nickel are preferable because of their high conductivity.Among them, copper is most preferable because of its especially highconductivity and small migration. As for the thermosetting resin, forexample, an epoxy resin, a phenol resin or a cyanate resin can be used.An epoxy resin is most preferable because of its high heat resistance.

[0063] In the circuit component built-in module 100 in Embodiment 1, thewiring patterns 102 a and 102 b are connected by the inner via 104filling a through-hole in the insulating substrate 101. As a result, inthe circuit component built-in module 100, the circuit components 103can be mounted with high density.

[0064] Furthermore, in the circuit component built-in module 100, theinorganic filler contained in the insulating substrate 101 swiftlyconducts the heat generated in the circuit components. Therefore, ahighly reliable circuit component built-in module can be obtained.

[0065] Furthermore, in the circuit component built-in module 100, thecoefficient of linear expansion, the heat conductivity, and thedielectric constant of the insulating substrate 101 can be controlledeasily by selecting a suitable organic filler for the insulatingsubstrate 101. A coefficient of linear expansion of the insulatingsubstrate 101 substantially equal to that of the semiconductor deviceprevents cracks or the like from occurring due to a temperature change.As a result, a reliable circuit component built-in module can beobtained. An improvement in the heat conductivity of the insulatingsubstrate 101 allows a reliable circuit component built-in module to beproduced even if the circuit components are mounted with high density. Alow dielectric constant of the insulating substrate 101 allows a modulefor high frequency circuit with little dielectric loss to be produced.

[0066] Furthermore, in the circuit component built-in module 100, theinsulating substrate 101 can shield the circuit components 103 from theexternal air, thus preventing deterioration of reliability due tohumidity.

[0067] Furthermore, in the circuit component built-in module 100 of thepresent invention, the insulating substrate 101 is formed of a mixtureof an inorganic filler and a thermosetting resin, so that the substrate101 can be produced easily without being sintered at a high temperatureunlike a ceramic substrate.

[0068] In the circuit component built-in module 100 shown in FIG. 1, thewiring pattern 102 a is not buried in the insulating substrate 101.However, the wiring pattern 102 a may be buried in the insulatingsubstrate 101 (refer to FIG. 3(h)).

[0069] In the circuit component built-in module 100 shown in FIG. 1, nocircuit component is mounded on the wiring pattern 102 a. However, acircuit component may be mounded on the wiring pattern 102 a, and thecircuit component built-in module may be molded with resin (the same isapplied to the following embodiments). The circuit components can bemounted with a higher density by mounting circuit components on thewiring pattern 102 a.

[0070] Embodiment 2

[0071] One embodiment of a method for producing the circuit componentbuilt-in module shown in FIG. 1 will be described with reference toFIGS. 2(a) to 2(h) of Embodiment 2. The materials and the circuitcomponents used in Embodiment 2 are the same as those described inEmbodiment 1.

[0072] FIGS. 2(a) to 2(h) are cross-sectional views showing a processsequence in one embodiment of a method for producing the circuitcomponent built-in module.

[0073] First, as shown in FIG. 2(a), a mixture of an inorganic fillerand a thermosetting resin is processed so as to form a mixture 200 inthe form of a sheet. An inorganic filler and an uncured thermosettingresin are mixed so as to form a paste mixture. The paste mixture ismolded in a predetermined thickness so as to form the mixture 200 in theform of a sheet (hereinafter, referred to as “sheet mixture”).

[0074] The sheet mixture 200 may be heated at a temperature below thecuring temperature of the thermosetting resin. The heat treatment allowsthe adhesion of the mixture 200 to be eliminated while maintaining theflexibility, thereby facilitating the subsequent processes. In addition,for a mixture comprising a thermosetting resin dissolved in a solvent, aheat treatment serves to remove the solvent partially.

[0075] Thereafter, as shown in FIG. 2(b), a through-hole 201 is formedin a desired position in the mixture 200 so as to form a sheet havingthe throughhole 201. The through-hole 201 can be formed by, for example,laser processing or processing with a drill or a mold. Laser processingis preferable because it allows formation of the through-hole 201 in afine pitch and generates no debris. In laser processing, carbon dioxidegas laser or excimer laser is preferably used to facilitate theprocessing. The throughhole 201 may be formed simultaneously when thepaste mixture is molded into the sheet mixture 200.

[0076] Thereafter, as shown in FIG. 2(c), a sheet having thethrough-hole 201 filled with a conductive resin composition 202 isformed by filling the through-hole 201 with the conductive resincomposition 202.

[0077] In parallel to the processes shown in FIGS. 2(a) to 2(c), asshown in FIG. 2(d), a circuit component 204 is flip-chip bonded to acopper foil. The circuit component 204 is electrically connected to thecopper foil 203 via a conductive adhesive 205. As for the conductiveadhesive 205, for example, a mixture of a thermosetting resin and gold,silver, copper, or a silver-palladium alloy can be used. Instead of theconductive adhesive 205, a bump produced by a gold wire bonding or asolder bump may be formed on the side of the circuit component 204beforehand, and the gold or the solder may be dissolved by a heattreatment so that the circuit component 204 can be mounted on the copperfoil 203. Furthermore, the solder bump can be used together with theconductive adhesive.

[0078] A sealing resin may be injected between the copper foil 203 andthe circuit component 204 mounted on the copper foil 203 (also in thefollowing embodiments, a sealing resin may be injected between a circuitcomponent and a copper foil or a circuit component and a wiringpattern). The injection of a sealing resin prevents the formation ofgaps between the semiconductor device and the wiring pattern whenburying the semiconductor device in the sheet in a subsequent process.An underfill resin, which is used for general flip chip bonding, can beused for the sealing resin.

[0079] In parallel to the processes shown in FIGS. 2(a) to 2(c), acopper foil 206 is formed, as shown in FIG. 2(e).

[0080] Thereafter, as shown in FIG. 2(f), the sheet of FIG. 2(c) issandwiched between the copper foil 203 provided with the circuitcomponent 204 and the copper foil 206 in a suitable position.

[0081] Then, as shown in FIG. 2(g), the sheet together with the copperfoils 203 and 206 are pressed, so that the circuit component 204 isburied in the sheet. Then, the sheet is heated so that the thermosettingresin in the mixture 200 and the conductive resin composition 202 iscured. Thus, the sheet in which the circuit component 204 is buried isformed. The heating is performed at a temperature equal to or higherthan a temperature at which the thermosetting resin in the mixture 200and the conductive resin composition 202 is cured (e.g., 150° C. to 260°C.). The mixture 200 serves as an insulating substrate 207, and theconductive resin composition 202 serves as an inner via 208. Thisprocess allows the copper foils 203 and 206, the circuit component 204and the insulating substrate 207 to strongly adhere to each othermechanically. The inner via 208 electrically connects the copper foils203 and 206. The mechanical strength of the circuit component module canbe improved by applying a pressure of 10 kg/cm² to 200 kg/cm² whileheating to cure the thermosetting resin in the mixture 200 and theconductive resin composition 202 (the same can apply in the followingembodiments).

[0082] Thereafter, as shown in FIG. 2(h), the copper foils 203 and 206are processed into wiring patterns 209 and 210.

[0083] Thus, the circuit component built-in module as described inEmbodiment 1 can be formed. The above-described method allows thecircuit component built-in module as described in Embodiment 1 to beproduced easily.

[0084] In Embodiment 2, the conductive resin composition 202 is used asa conductive substance with which the through-hole 201 is filled.However, the conductive substance is not limited thereto, and anythermosetting conductive substance can be used, which also applies tothe following embodiments.

[0085] Embodiment 3

[0086] Another embodiment of a method for producing the circuitcomponent built-in module shown in FIG. 1 will be described withreference to FIGS. 3(a) to 3(h) of Embodiment 3. The materials and thecircuit components used in Embodiment 3 are the same as those describedin Embodiment 1.

[0087] FIGS. 3(a) to 3(h) are cross-sectional views showing a processsequence for producing a circuit component built-in module in Embodiment3.

[0088] First, as shown in FIG. 3(a), a mixture comprising an inorganicfiller and a thermosetting resin is processed into a sheet mixture 300.Since this process is the same as that described with reference to FIG.2(a), it will not be described further herein.

[0089] Thereafter, as shown in FIG. 3(b), a through-hole 301 is formedin a desired position of the mixture 300. Since this process is the sameas that described with reference to FIG. 2(b), it will not be describedfurther herein.

[0090] Then, as shown in FIG. 3(c), the through-hole 301 is filled witha conductive resin composition 302, so as to form a sheet with thethrough-hole 301 filled with the conductive resin composition 302.

[0091] In parallel to the processes shown in FIGS. 3(a) to 3(c), asshown in FIG. 3(d), a wiring pattern 303 is formed on a release film305, and a circuit component 304 is mounted on the wiring pattern 303.The circuit component 304 is mounted in the same manner as describedwith reference to FIG. 2(d), so that it will not be described furtherherein. For example, polyethylene terephthalate or polyphenylene sulfidecan be used for the release film 305. The wiring pattern 303 can beformed by attaching a copper foil to the release film 305 and thenperforming photolithography and etching. Instead, a metal lead framethat is formed by etching or stamping can be used for the wiring pattern303.

[0092] In parallel to the processes shown in FIGS. 3(a) to 3(c), asshown in FIG. 3(e), a wiring pattern 306 is formed on a release film307. The wiring pattern 306 can be formed in the same manner as thewiring pattern 303.

[0093] Thereafter, as shown in FIG. 3(f), the sheet of FIG. 2(c) issandwiched between the release films 305 and 307 in a suitable positionso that the wiring patterns 303 and 306 and the conductive substance 302are connected in a desired portion.

[0094] Then, as shown in FIG. 3(g), the sheet together with the releasefilms 305 and 307 is pressed and heated so that the thermosetting resinin the mixture 300 and the conductive resin composition 302 is cured.Thus, the sheet in which the circuit component 304 and the wiringpatterns 303 and 306 are buried is formed. The heating is performed at atemperature equal to or higher than a temperature at which thethermosetting resin in the mixture 300 and the conductive resincomposition 302 is cured (e.g., 150° C. to 260° C.). The mixture 300serves as an insulating substrate 308, and the conductive resincomposition 302 serves as an inner via 309. The inner via 309electrically connects the wiring patterns 303 and 306.

[0095] Thereafter, as shown in 3(h), the release film 305 and 307 arepeeled from the sheet of FIG. 3(g).

[0096] Thus, the circuit component built-in module as described inEmbodiment 1 can be produced. The above-described method makes it easyto produce the circuit component built-in module as described inEmbodiment 1.

[0097] In this method, the release film 307 on which the wiring pattern306 has been formed earlier is used, so that the obtained circuitcomponent built-in module has a smooth surface as a result of buryingthe wiring pattern 306 in the insulating substrate 308. The smoothnessof the surface makes it possible to mount the components on the wiringpattern 306 with high density and thus to achieve higher density circuitcomponents.

[0098] Embodiment 4

[0099] One embodiment of a circuit component built-in module having amultilayered structure of the present invention will be described withreference to FIG. 4 of Embodiment 4. FIG. 4 is a perspectivecross-sectional view of a circuit component built-in module 400 of thisembodiment.

[0100] Referring to FIG. 4, the circuit component built-in module 400 inEmbodiment 4 includes an insulating substrate 401 comprising insulatingsubstrates 401 a, 401 b and 401 c, wiring patterns 402 a, 402 b, 402 cand 402 d formed on one principal plane and in the internal portion ofthe insulating substrate 401, a circuit component 403 arranged in theinternal portion of the insulating substrate 401 and connected to thewiring patterns 402 a, 402 b or 402 c, and an inner via 404 forelectrical connection between the wiring patterns 402 a, 402 b, 402 cand 402 d.

[0101] The insulating substrates 401 a, 401 b and 401 c are formed of amixture comprising an inorganic filler and a thermosetting resin. Forexample, Al₂O₃, MgO, BN, AlN or SiO₂ can be used for the inorganicfiller. The inorganic filler is preferably contained in an amount of 70wt % to 95 wt % on the basis of the mixture. The average particlediameter of the inorganic filler is preferably 0.1 μm to 100 μm.Preferable examples of the thermosetting resin include an epoxy resin, aphenol resin, or a cyanate resin, which are highly resistant againstheat. An epoxy resin is most preferable because of its especially highheat resistance. The mixture may further comprise a dispersant, acoloring agent, a coupling agent or a releasing agent.

[0102] The wiring patterns 402 a, 402 b, 402 c and 402 d are the same asthe wiring patterns 102 a and 102 b, which are described in Embodiment1, and they will not be described further herein.

[0103] The circuit component 403 includes, for example, an activecomponent 403 a and a passive component 403 b. A semiconductor devicesuch as a transistor, an IC, and an LSI can be used for the activecomponent 403 a. The semiconductor device may be a semiconductor barechip. A chip resistor, a chip capacitor or a chip inductor can be usedfor the passive component 403 b. The circuit component 403 may notinclude the passive component 403 b.

[0104] The active component 403 a is connected to the wiring patterns402 a, 402 b, and 403 c, for example, by flip chip bonding. Thesemiconductor bare chips may be flip-chip bonded so that circuitcomponents can be mounted with high density.

[0105] The inner via 404 is formed of a conductive substance. Forexample, a conductive resin composition comprising metal particles and athermosetting resin can be used for the inner via 404. Examples of themetal particles include gold, silver, copper and nickel. Gold, silver,copper and nickel are preferable because of their high conductivity.Among them, copper is most preferable because of its especially highconductivity and small migration. As for the thermosetting resin, forexample, an epoxy resin, a phenol resin or a cyanate resin can be used.An epoxy resin is most preferable because of its high heat resistance.

[0106] In the circuit component built-in module 400 shown in FIG. 4, thewiring pattern 402 d is not buried in the insulating substrate 401 c.However, the wiring pattern 402 d may be buried in the insulatingsubstrate 401 c (see to FIG. 6(g)).

[0107] Although FIG. 4 shows the circuit component built-in module 400having a three layered structure, a structure having any number oflayers can be formed depending on the design, and the same applies tothe following embodiments.

[0108] Embodiment 6

[0109] Another embodiment of a method for producing the circuitcomponent built-in module of Embodiment 4 will be described withreference to FIGS. 5(a) to 5(h) of Embodiment 5. The material and thecircuit components used in Embodiment 5 are the same as those describedin Embodiment 4.

[0110] FIGS. 5(a) to 5(h) are cross-sectional views showing a processsequence for producing a circuit component built-in module in thisembodiment.

[0111] First, as shown in FIG. 5(a), a mixture comprising an inorganicfiller and a thermosetting resin is processed into a sheet mixture 500.A through-hole is filled with a conductive resin composition 501, so asto form a sheet with the through-hole filled with the conductive resincomposition 501. Since this process is the same as that described withreference to FIGS. 2(a) to 2(c), it will not be described furtherherein.

[0112] On the other hand, a wiring pattern 506 is formed on a releasefilm 503, and an active component 504 and a passive component 505 aremounted on the wiring pattern 506. This process is the same as thatdescribed with reference to FIG. 3(d), so that it will not be describedfurther herein.

[0113] Thereafter, the sheet of FIG. 5(a) is positioned and superimposedon the release film 503, and they are pressed. Then, the release film503 is peeled off, so that the sheet in which the wiring pattern 506,the active component 504 and the passive component 505 are buried isformed, as shown in FIG. 5(b).

[0114] In parallel to the processes of FIGS. 5(a) and 5(b), a pluralityof sheets in which the wiring pattern 506 and the circuit components areburied are formed in the same manner as those shown in FIGS. 5(a) and5(b) (see to FIGS. 5(c) and 5(d), and FIGS. 5(e) and 5(f)). The wiringpattern 506 and the circuit components are different from layer to layerin accordance with the design.

[0115] Thereafter, as shown in FIG. 5(g), the sheet of FIG. 5(d) issandwiched between the sheets of FIGS. 5(b) and 5(f) in a suitableposition. Then, a copper foil 507 is superimposed on a principal planeof the sheet of FIG. 5(f) in which the wiring pattern is not formed.

[0116] Thereafter, the sheets and the copper foil 507 are positioned andplaced on one another in the process shown in FIG. 5(g), pressed andheated, so that a sheet having a multilayered structure can be formed,as shown in FIG. 5(h). The heating is performed at a temperature equalto or higher than a temperature at which the thermosetting resin in themixture 500 and the conductive resin composition 501 is cured (e.g.,150° C. to 260° C.). The mixture 500 serves as an insulating substrate508, and the conductive resin composition 501 serves as an inner via509. This process allows the circuit components 504 and 505, the copperfoil 507 and the insulating substrate 508 to strongly adheremechanically. The inner via 509 electrically connects the wiring pattern506 and the copper foil 507. Then, the copper foil 507 is processed intoa wiring pattern 510.

[0117] Thus, a circuit component built-in module having a multilayeredstructure can be formed. The above-described method allows a circuitcomponent built-in module having a multilayered structure to be producedeasily.

[0118] Embodiment 6

[0119] Another embodiment of a method for producing the circuitcomponent built-in module of Embodiment 4 will be described withreference to FIGS. 6(a) to 6(g) of Embodiment 6. The material and thecircuit components used in Embodiment 6 are the same as those describedin Embodiment 4.

[0120] FIGS. 6(a) to 6(g) are cross-sectional views showing a processsequence for producing a circuit component built-in module in thisembodiment.

[0121] First, as shown in FIG. 6(a), a mixture comprising an inorganicfiller and a thermosetting resin is processed into a sheet mixture 600.A throughhole is filled with a conductive resin composition 601, so asto form a sheet with the through-hole filled with the conductive resincomposition 601. Since this process is the same as that described withreference to FIGS. 2(a) to 2(c), it will not be described furtherherein.

[0122] On the other hand, a wiring pattern 606 is formed on a releasefilm 603, and an active component 604 and a passive component 605 aremounted on the wiring pattern 606. This process is the same as thatdescribed with reference to FIG. 3(d), so that it will not be describedfurther herein.

[0123] Thereafter, the sheet of FIG. 6(a) is positioned and superimposedon the release film 603, and they are pressed. Then, the release film603 is peeled off, so that the sheet in which the wiring pattern 606,the active component 604 and the passive component 605 are buried isformed, as shown in FIG. 6(b).

[0124] In parallel to the processes of FIGS. 6(a) and 6(b), a pluralityof sheets in which the wiring pattern 606 and the circuit components areburied are formed in the same manner as those shown in FIGS. 6(a) and6(b) (refer to FIGS. 6(c) and 6(d)). The wiring pattern 606 and thecircuit components are different from layer to layer in accordance withthe design.

[0125] In parallel to the processes of FIGS. 6(a) and 6(b), as shown inFIG. 6(e), a wiring pattern 607 is formed on the release film 603.

[0126] Thereafter, as shown in FIG. 6(f), the sheet of FIG. 6(d) ispositioned and superimposed on the sheet of FIG. 6(b). Then, the releasefilm 603 of FIG. 6(e) is superimposed on a principal plane of the sheetof FIG. 6(d) on which the wiring pattern 606 is not formed so that thewiring pattern 607 on the release film 603 faces inwards

[0127] Thereafter, the sheets and the release film 603 are positionedand attached to each other in the process shown in FIG. 6(f), pressedand heated, so that a sheet having a multilayered structure can beformed, as shown in FIG. 6(g). The heating is performed at a temperatureequal to or higher than a temperature at which the thermosetting resinin the mixture 600 and the conductive resin composition 601 is cured(e.g., 150° C. to 260° C.). The mixture 600 serves as an insulatingsubstrate 608, and the conductive resin composition 601 serves as aninner via 609. This process allows the active component 604, the passivecomponent 605, the wiring pattern 606 and 607 and the insulatingsubstrate 608 to strongly adhere mechanically. The inner via 609electrically connects the wiring patterns 606 and 607.

[0128] Then, the release film 603 is peeled from the sheet having amultilayered structure, so that a circuit component built-in modulehaving a multilayered structure can be formed.

[0129] Thus, the above-described method allows a circuit componentbuilt-in module having a multilayered structure to be produced easily.

EXAMPLES

[0130] Hereinafter, the present invention will be specifically describedby way of examples.

Example 1

[0131] In the production of a circuit component built-in module of thepresent invention, an example of a method for producing an insulatingsubstrate formed of a mixture comprising an inorganic filler and athermosetting resin will be described at first.

[0132] In this example, an insulating substrate was produced with acomposition shown in Table 1. Sample 1 in Table 1 is a comparativeexample. TABLE 1 Linear Breakdown Inorganic filler Thermosetting resinHeat expansion Dielectric Dielectric voltage Sample amount amountAdditive conductivity coefficient constant loss (AC) No. type (wt %)type (wt %) (wt %) (W/mK) (ppm/° C.) 1 MHz 1 MHz (%) kV/mm 1 Al₂O₃ 60liquid 39.8 carbon 0.52 45 3.5 0.3 8.1 2 Al₂O₃ 70 epoxy 29.8 black 0.8732 4.7 0.3 10.1 3 Al₂O₃ 80 resin 19.8 (0.2) 1.2 26 5.8 0.3 16.5 4 Al₂O₃85 WE-2025 14.8 2.8 21 6.1 0.2 15.5 5 Al₂O₃ 90 9.8 4.5 16 6.7 0.2 18.7 6Al₂O₃ 95 4.8 5.5 11 7.1 0.2 17.1 7 MgO 78 liquid 21.8 carbon 4.2 24 8.10.4 15.2 8 BN 77 epoxy 22.8 black 5.5 10 6.8 0.3 17.4 9 AlN 85 resin14.8 (0.2) 5.8 18 7.3 0.3 19.3 10 SiO₂ 75 WE-2025 24.8 2.2 7 3.5 0.218.2 11 Al₂O₃ 90 phenol 9.8 carbon 4.1 31 7.7 0.5 13.2 resin black (0.2)12 Al₂O₃ 90 cyanate 9.8 dispersant 3.8 15 6.7 0.2 14.5 resin (0.2)

[0133] In this example, an epoxy resin manufactured by Nippon Pelnox(WE-2025, comprising an acid anhydrous hardening agent) was used for theliquid epoxy resin. A phenol resin manufactured by Dainippon Ink andChemicals, Inc. (Fenolight, VH-4150) was used for the phenol resin. Acyanate resin manufactured by Asahi Ciba (AroCy, M-30) was used for thecyanate resin. In this example, carbon black or a dispersant was addedas an additive.

[0134] A sheet mixture was produced in the following manner. First, apredetermined amount of a paste mixture obtained by mixing thecomponents in the composition shown in Table 1 was poured and spread ona release film. The paste mixture was prepared by mixing an inorganicfiller and a liquid thermosetting resin by an agitator for about 10minutes. The agitator used in this example operates in such a mannerthat an inorganic filler and a liquid thermosetting resin are placed ina container, and the container itself rotates so as to stir the mixturein the container. The mixture obtained by using this agitator isdispersed sufficiently, even if the mixture has a relatively highviscosity. A polyethylene terephthalate film having a thickness of 75 μmwas used for the release film, and the surface of the film was subjectedto a release treatment with silicon.

[0135] Next, another release film was placed on the paste mixture on therelease film, and pressing was performed by a pressurizing press so asto form a sheet mixture having a thickness of 500 μm.

[0136] Next, the sheet mixture sandwiched between the release films washeated together with the release films under the conditions that allowthe elimination of the adhesion of the sheet mixture. The heat treatmentwas performed at 120° C. for 15 minutes. This heat treatment foreliminating the adhesion of the sheet mixture facilitates peeling of therelease films. The liquid epoxy resin used in this example starts to becured at 130° C., and therefore the epoxy resin was uncured (B stage)under the condition of this treatment.

[0137] Next, the release films were peeled from the sheet mixture, andthe sheet mixture was sandwiched between heat resistant release films(PPS: polyphenylene sulfide, a thickness of 75 μm), and heated at atemperature of 170° C. for curing while being pressed at a pressure of50 kg/cm².

[0138] Next, the heat resistant release films were peeled from the sheetmixture. Thus, an insulating substance was obtained.

[0139] After processing the insulating substrate into a predeterminedsize, the heat conductivity, the coefficient of linear expansion, thebreakdown voltage, or the like were measured. The breakdown voltage ofthe insulating substrate indicates the adhesion between the inorganicfiller and the thermosetting resin that are materials for the insulatingsubstrate. More specifically, when the adhesion between the inorganicfiller and the thermosetting resin is poor, micro gaps therebetween areformed so that the breakdown voltage deteriorates. Such micro gapsdeteriorate the reliability of the circuit component built-in module.The heat conductivity was obtained in the following manner. A surface ofa sample of 10 mm×10 mm was heated in contact with a heater, and anincrease in the temperature on the other surface was measured. The heatconductivity was calculated based on the increase in the temperature onthe other surface. The coefficient of linear expansion was obtained inthe following manner. A change in the size of the insulating substratewas measured when the temperature was raised from room temperature to140° C., and the coefficient of linear expansion was calculated based onthe average value of the change. The breakdown voltage was obtained inthe following manner. A breakdown voltage was calculated when an ACvoltage was applied to the thickness direction of the insulatingsubstrate, and a breakdown voltage per unit thickness was calculated.

[0140] As shown in Table 1, when Al₂O₃ was used for the inorganicfiller, the insulating substrate produced according to theabove-described method had more than about 10 times the heatconductivity of a conventional glass-epoxy substrate (0.2 w/mK to 0.3w/mK). When the content of Al₂O₃ was about 85 wt % or more, the heatconductivity was 2.8 w/mK or more. A₂O₃ is also advantageous forreducing cost.

[0141] When AlN or MgO was used as the inorganic filler, theconductivity was as good as or better than that when Al₂O₃ was used.

[0142] When amorphous SiO₂ was used for the inorganic filler, thecoefficient of linear expansion became closer to that of a siliconsemiconductor (a coefficient of linear expansion of 3×10⁻⁶/° C.).Therefore, the insulating substrate comprising amorphous SiO₂ as theinorganic filler is preferably used as a flip chip substrate directly onwhich a semiconductor is mounted.

[0143] Furthermore, when amorphous SiO₂ was used for the inorganicfiller, an insulating substrate having a low dielectric constant wasobtained. SiO₂ is advantageous in view of its low specific gravity. Acircuit component built-in module comprising SiO₂ as the inorganicfiller is preferably used as a high frequency module such as a cellularphone.

[0144] When BN was used for the inorganic filler, an insulatingsubstrate having a high heat conductivity and a low coefficient oflinear expansion was obtained.

[0145] As shown in Table 1, the breakdown voltages of the insulatingsubstrates of all the samples except sample 1 (the comparative example),which comprises 60 wt % of Al₂O₃ as the inorganic filler, were 10 kV/mmor more. Generally, a breakdown voltage of 10 kV/mm or more can betranslated to mean that the adhesion between the inorganic filler andthe thermosetting resin is good. Therefore, it is preferable that thecontent of the inorganic filler is 70 wt % or more.

[0146] Furthermore, when the content of the thermosetting resin is low,the strength of the insulating substrate is low. Therefore, it ispreferable that the content of the thermosetting resin is 4.8 wy % ormore.

Example 2

[0147] An illustrative circuit component built-in module produced in themethod described in Embodiment 2 will be described in this example.

[0148] The insulating substrate used in this example comprises 90 wt %of Al₂O₃(S-40 manufactured by Showa Denko K.K., spherical particles, anaverage particle diameter of 12 μm), 9.5 wt % of liquid epoxy resin(EF-450 manufactured by Nippon Rec Co. Ltd.), 0.2 wt % of carbon black(manufactured by Toyo Carbon) and 0.3 wt % of a coupling agent (46B,titanate based coupling agent manufactured by Ajinomoto Co., Inc.).

[0149] The materials for the insulating substrate were treated under thesame conditions as those in Example 1, so as to produce a sheet having athickness of 500 μm. The sheet was cut into a predetermined size, andthrough-holes of 0.15 mm diameter for inner-via-hole connection wereformed by using a carbon dioxide gas laser (see FIG. 2(b)).

[0150] The through-holes were filled with a conductive resin compositionby a screen printing method (see FIG. 2(c)). The conductive resincomposition was obtained by mixing 85 wt % of spherical copperparticles, 3 wt % of bisphenol A epoxy resin (Epicoat 828 manufacturedby Yuka Shell Epoxy), 9 wt % of glycidyl ester based epoxy resin (YD-171manufactured by Toto Kasei), and 3 wt % of amine adduct hardening agent(MY-24 manufactured by Ajinomoto Co., Inc.).

[0151] Next, one surface of a copper foil having a thickness of 35 μmwas made rough, and a semiconductor device was flip-chip bonded onto therough surface with a conductive adhesive (see FIG. 2(d)).

[0152] Then, the sheet with the through-holes filled with the conductiveresin composition was sandwiched between the copper foil provided with asemiconductor device and another separately prepared copper foil havinga thickness of 35 μm (one surface of which was made rough) in a suitableposition (see FIG. 2(f)). The sheet was sandwiched between the copperfoils so that the rough surfaces of the copper foils were in contactwith the sheet.

[0153] Then, heating and pressing were performed by a hot-press at atemperature of 120° C. and a pressure of 10 kg/cm² for 5 minutes. Sincethe thermosetting resin in the sheet was softened by heating at atemperature below the curing temperature, the semiconductor device waseasily buried in the sheet.

[0154] Then, the heating temperature was raised to 175° C., and heatingwas performed for 60 minutes (see FIG. 2(g)). This heating allowed theepoxy resin in the sheet and the epoxy resin in the conductive resincomposition to be cured, so that the semiconductor device and the copperfoils and the sheet were strongly connected mechanically. This heatingalso allowed the conductive resin composition and the copper foils to beconnected electrically (through inner-via connection) and mechanically.

[0155] Then, the copper foil on the surface of the sheet in which thesemiconductor device was buried was etched in a photolithography processand an etching process so as to form a wiring pattern (see FIG. 2(h)).Thus, a circuit component built-in module was produced.

[0156] In order to evaluate the reliability of the circuit componentbuilt-in module produced in this example, a solder reflow test and atemperature cycle test were conducted. The solder reflow test wasconducted with a belt type reflow tester, in which a 10 second cycle wasrepeated 10 times at a maximum temperature of 260° C. The temperaturecycle test was conducted by allowing the circuit component built-inmodule to stand at 125° C. for 30 minutes and then at −60° C. for 30minutes per cycle, and repeating this cycle for a total of 200 cycles.

[0157] In either the solder reflow test or the temperature cycle test,no cracks were generated in the circuit component built-in module inthis example, and abnormality was not recognized, even if a supersonicflaw detector was used. These tests confirmed that the semiconductordevice and the insulating substrate adhered to each other tightly. Aresistance value of the inner—via connection by the conductive resincomposition was not substantially changed between measurements madebefore and after the tests.

Example 3

[0158] An illustrative circuit component built-in module produced in themethod described in Embodiment 3 will be described in this example.

[0159] First, a sheet (500 μm thick) having through-holes filled with aconductive resin composition was produced in the same method as that inExample 2 (see FIG. 3(c)).

[0160] Next, a copper foil having a thickness of 35 μm was adhered to arelease film (formed of polyphenylene sulfide and 150 μm thick) with anadhesive. One surface of the copper foil was rough, and the other smoothsurface of the copper foil was adhered to the release film.

[0161] Then, the copper foil on the release film was etched in aphotolithography process and an etching process so as to form a wiringpattern. Furthermore, a semiconductor device was flip-chip bonded ontothe wiring pattern with a solder bump (see FIG. 3(d)).

[0162] Then, a sealing resin was injected in a gap between the wiringpattern and the semiconductor device on the wiring pattern. Morespecifically, a hot plate heated to 70° C. was tilted, and the releasefilm having the wiring pattern provided with the semiconductor devicewas placed on the hot plate. Thereafter, a sealing resin was graduallyinjected between the semiconductor device and the wiring pattern with aninjection. The injection of the sealing resin between the semiconductordevice and the wiring pattern was completed in about 10 seconds. The hotplate was heated for the purpose of lowering the viscosity of thesealing resin so that the injection was completed in a short time. Thehot plate was tilted for the purpose of facilitating the injection. Asfor the sealing resin, a product manufactured by Techno alpha Co. Ltd.,EL18B, was used. The product, EL18B, is a resin comprising one-componentepoxy resin mixed with SiO₂ powders.

[0163] On the other hand, in parallel to the above-described process, arelease film (formed of polyphenylene sulfide and 150 μm thick) having awiring pattern formed on one surface thereof was produced (see FIG.3(e)).

[0164] Next, the sheet having the through-holes filled with theconductive resin composition was sandwiched between the release filmwith the semiconductor device bonded thereon and the release film havingthe wiring pattern on one surface thereof in a suitable position (seeFIG. 3(f)).

[0165] Then, heating and pressing were performed by a hot-press at atemperature of 120° C. and a pressure of 10 kg/cm² for 5 minutes. Sincethe thermosetting resin in the sheet was softened by heating at atemperature below the curing temperature, the semiconductor device andthe wiring pattern were easily buried in the sheet.

[0166] Then, the heating temperature was raised to 175° C., and heatingwas performed for 60 minutes (see FIG. 3(g)). This heating allowed theepoxy resin in the sheet and the conductive resin composition to becured, so that the semiconductor device and the wiring pattern and sheetwere strongly connected mechanically. This heating also allowed theconductive resin composition and the wiring pattern to be connectedelectrically (through inner-via connection) and mechanically.Furthermore, this heating allowed the sealing resin injected between thesemiconductor device and the wiring pattern to be cured.

[0167] Then, the release film was peeled from the sheet (see FIG. 3(h)).The release film made of polyphenylene sulfide has a heat resistanceagainst the above-mentioned heating temperature or more. Furthermore,the rough surface of the copper foil was adhered to the sheet and theinner via, and the smooth surface of the copper foil was adhered to therelease film. Therefore, the adhesion between the sheet and the innervia and the copper foil was larger than that between the release filmand the copper foil. This allowed the release film alone to be peeledoff. Thus, a circuit component built-in module was produced.

[0168] In order to evaluate the reliability of the circuit componentbuilt-in module produced in this example, a solder reflow test and atemperature cycle test were conducted under the same conditions as thosein Example 2.

[0169] In either the solder reflow test or the temperature cycle test,no cracks were generated in the circuit component built-in module inthis example, and abnormality was not recognized, even if a supersonicflaw detector was used. These tests confirmed that the semiconductordevice and the insulating substrate adhered to each other tightly. Aresistance value of the inner—via connection by the conductive resincomposition was not substantially changed between measurements madebefore and after the tests.

Example 4

[0170] An illustrative circuit component built-in module having amultilayered structure produced in the method described in Embodiment 5will be described in this example.

[0171] In Example 4, a semiconductor device and a chip component wereused as the circuit components.

[0172] First, a sheet having through-holes filled with a conductiveresin composition was formed in the same manner as in Example 2.

[0173] Next, the sheet having through-holes filled with a conductiveresin composition was positioned and superimposed on a release film(made of polyphenylene sulfide) provided with a wiring pattern having acircuit component flip-chip bonded thereon (see FIG. 5(a)).

[0174] Then, heating and pressing were performed by a hot-press at atemperature of 120° C. and a pressure of 10 kg/cm² for 5 minutes. Sincethe thermosetting resin in the sheet was softened by heating at atemperature below the curing temperature, the circuit component waseasily buried in the sheet. Then, the release film was peeled from thesheet so as to form a sheet in which the circuit component was buried(see FIG. 5(b)).

[0175] A plurality of sheets were prepared in this manner, and theplurality of sheets and a copper foil were positioned and superimposedon one another (FIG. 5(g)).

[0176] Then, heating and pressing were performed by a hot-press at atemperature of 175° C. and a pressure of 50 kg/cm² for 60 minutes. Thisheating and pressing treatment allowed the copper foil and the pluralityof sheets in which circuit components were buried to be integrated, andthus one sheet was formed. The heating and pressing treatment allowedthe epoxy resin in the sheet and the conductive resin composition to becured, so that the circuit components and the wiring pattern and thesheet were strongly connected mechanically. The heating and pressingtreatment also allowed the copper foil and the wiring pattern and theconductive resin composition to be connected electrically (throughinner-via connection) and mechanically.

[0177] Then, the copper foil on the surface of the sheet in which thecircuit components were buried was etched in a photolithography processand an etching process so as to form a wiring pattern (see FIG. 5(h)).Thus, a circuit component built-in module having a multilayeredstructure was produced.

[0178] In order to evaluate the reliability of the circuit componentbuilt-in module produced in this example, a solder reflow test and atemperature cycle test were conducted in the same conditions as inExample 2.

[0179] In either the solder reflow test or the temperature cycle test,no cracks were generated in the circuit component built-in module inthis example, and abnormality was not recognized, even if a supersonicflaw detector was used. These tests confirmed that the semiconductordevice and the insulating substrate adhered to each other tightly. Aresistance value of the inner—via connection by the conductive resincomposition was not substantially changed between measurements madebefore and after the tests.

Example 5

[0180] An illustrative circuit component built-in module having amultilayered structure produced in the method described in Embodiment 6will be described in this example.

[0181] First, a sheet having through-holes filled with a conductiveresin composition was formed in the same manner as in Example 2. Next,the sheet having through-holes filled with a conductive resincomposition was positioned and superimposed on a release film (made ofpolyphenylene sulfide) provided with a wiring pattern having a circuitcomponent flip-chip bonded thereon (see FIG. 6(a)).

[0182] Then, heating and pressing were performed by a hot-press at atemperature of 120° C. and a pressure of 10 kg/cm² for 5 minutes. Sincethe thermosetting resin in the sheet was softened by heating at atemperature below the curing temperature, the circuit component waseasily buried in the sheet. The release film was peeled from the sheetso as to form a sheet (see FIG. 6(b)). Another sheet in which a circuitcomponent was buried was formed in the same manner (see FIG. 6(d)).

[0183] Then, wiring patterns were formed on one surface of a releasefilm made of polyphenylene sulfide (see FIG. 6(e)).

[0184] Then, the two sheets with the circuit components buried thereinand the release film provided with the wiring patterns were positionedand superimposed on one another (see FIG. 6(f)).

[0185] Then, heating and pressing were performed by a hot-press at atemperature of 175° C. and a pressure of 50 kg/cm² for 60 minutes. Thisheating and pressing treatment allowed the release film and theplurality of sheets with the circuit components buried therein to beintegrated, and thus one sheet was formed. The heating and pressingtreatment allowed the epoxy resin in the sheet to be cured, so that thecircuit components and the wiring pattern and the sheet were stronglyconnected mechanically. The heating and pressing treatment also allowedthe epoxy resin in the conductive resin composition to be cured, so thatthe wiring pattern and the conductive resin composition were connectedelectrically (through inner-via connection) and mechanically.

[0186] Then, the release film was peeled from the integrated sheet sothat a circuit component built-in module having a multilayered structurewas produced (see FIG. 6(g)).

[0187] In order to evaluate the reliability of the circuit componentbuilt-in module produced in this example, a solder reflow test and atemperature cycle test were conducted in the same conditions as inExample 2.

[0188] In either the solder reflow test or the temperature cycle test,no cracks were generated in the circuit component built-in module inthis example, and abnormality was not recognized, even if a supersonicflaw detector was used. These tests confirmed that the semiconductordevice and the insulating substrate adhered to each other tightly. Aresistance value of the inner—via connection by the conductive resincomposition was not substantially changed between measurements madebefore and after the tests.

[0189] The invention may be embodied in other forms without departingfrom the spirit or essential characteristics thereof. The embodimentsdisclosed in this application are to be considered in all respects asillustrative and not limitative, the scope of the invention is indicatedby the appended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are intended to be embraced therein.

What is claimed is:
 1. A circuit component built-in module comprising:an insulating substrate formed of a mixture comprising 70 wt % to 95 wt% of an inorganic filler and a thermosetting resin; a plurality ofwiring patterns formed on at least a principal plane of the insulatingsubstrate; a circuit component arranged in an internal portion of theinsulating substrate and electrically connected to the wiring patterns;and an inner via formed in the insulating substrate for electricallyconnecting the plurality of wiring patterns.
 2. A circuit componentbuilt-in module according to claim 1, wherein the circuit componentincludes an active component, and the inner via is formed of aconductive resin composition.
 3. A circuit component built-in moduleaccording to claim 1, wherein the wiring patterns are further formed inan internal portion of the insulating substrate.
 4. A circuit componentbuilt-in module according to claim 1, wherein the circuit component isshielded from external air by the insulating substrate.
 5. A circuitcomponent built-in module according to claim 1, wherein thethermosetting resin comprises at least one thermosetting resin selectedfrom the group consisting of an epoxy resin, a phenol resin and acyanate resin.
 6. A circuit component built-in module according to claim1, wherein the inorganic filler comprises at least one inorganic fillerselected from the group consisting of Al₂O₃, MgO, BN, AlN and SiO₂.
 7. Acircuit component built-in module according to claim 1, wherein anaverage particle diameter of the inorganic filler is 0.1 μm to 100 μm.8. A circuit component built-in module according to claim 1, wherein thewiring patterns comprise at least one conductive substance selected fromthe group consisting of copper and a conductive resin composition.
 9. Acircuit component built-in module according to claim 1, wherein thewiring patterns comprise lead frames formed by etching or stamping. 10.A circuit component built-in module according to claim 1, wherein thecircuit component comprises at least one component selected from thegroup consisting of a chip resistor, a chip capacitor and a chipinductor.
 11. A circuit component built-in module according to claim 1,wherein the mixture further comprises at least one additive selectedfrom the group consisting of a dispersant, a coloring agent, a couplingagent and a releasing agent.
 12. A circuit component built-in moduleaccording to claim 1, wherein the insulating substrate has a coefficientof linear expansion of 8×10⁻⁶/° C. to 20×10⁻⁶/° C. and a heatconductivity of 1 w/mK to 10 w/mK.
 13. A circuit component built-inmodule according to claim 2, wherein the active component comprises asemiconductor bare chip, and the semiconductor bare chip is flip-chipbonded onto the wiring pattern.
 14. A circuit component built-in moduleaccording to claim 2, wherein the conductive resin composition comprisesmetal particles of at least one metal selected from the group consistingof gold, silver, copper and nickel as a conductive component, and anepoxy resin as a resin component.
 15. A method for producing a circuitcomponent built-in module comprising the steps of: processing a mixturecomprising 70 wt % to 95 wt % of an inorganic filler and an uncuredthermosetting resin into a first sheet having a through-hole; fillingthe through-hole with a thermosetting conductive substance so as to forma second sheet having the through-hole filled with the thermosettingconductive substance; mounting a circuit component on a wiring patternportion in a first film; positioning and superimposing the second sheeton the side of the first film where the circuit component is mounted,and superimposing a second film having a wiring pattern portion on thesecond sheet, thereby forming a third sheet in which the circuitcomponent is buried; and heating the third sheet so as to form a fourthsheet in which the thermosetting resin and the conductive substance arecured.
 16. The method for producing a circuit component built-in moduleaccording to claim 15, wherein the circuit component comprises an activecomponent, and the conductive substance comprises a conductive resincomposition.
 17. The method for producing a circuit component built-inmodule according to claim 15, wherein the first and second films areformed of copper foils, and the method further comprises a step ofremoving the copper foils in a portion other than the wiring patternportions so as to form wiring patterns, said step of removing the copperfoils is after the step of forming the fourth sheet.
 18. The method forproducing a circuit component built-in module according to claim 15,wherein the first and second films are formed of release films havingwiring patterns formed on one principal plane thereof, and the methodfurther comprises a step of peeling the release films from the fourthsheet, said step of peeling the release films is after the step offorming the fourth sheet.
 19. The method for producing a circuitcomponent built-in module according to claim 15, the method furthercomprising a step of injecting a sealing resin between the circuitcomponent and the wiring pattern, said step of injecting a sealing resinis after the step of mounting the circuit component on the wiringpattern portion.
 20. The method for producing a circuit componentbuilt-in module according to claim 15, wherein the thermosetting resinand the conductive substance are heated at 150° C. to 260° C. forcuring.
 21. The method for producing a circuit component built-in moduleaccording to claim 15, wherein the thermosetting resin and theconductive substance are pressed at a pressure of 10 kg/cm² to 200kg/cm² while being heated for curing.
 22. The method for producing acircuit component built-in module according to claim 15, wherein thestep of forming the first sheet further comprises a step of heating thesheet mixture at a temperature below a cure temperature of thethermosetting resin, thereby eliminating adhesion of the sheet mixture,said step of heating the sheet mixture is after the step of forming themixture into the sheet.
 23. The method for producing a circuit componentbuilt-in module according to claim 15, wherein the step of forming thethird sheet by burying the circuit component in the second sheet isperformed at a temperature below a cure temperature of the thermosettingresin.
 24. The method for producing a circuit component built-in moduleaccording to claim 15, wherein the step of mounting the circuitcomponent on the wiring pattern comprises a step of electrically andmechanically connecting the circuit component and the wiring patternwith solder.
 25. The method for producing a circuit component built-inmodule according to claim 16, wherein the step of mounting the activecomponent on the wiring pattern comprises a step of electricallyconnecting a gold bump of the active component and the wiring patternwith a conductive adhesive.
 26. A method for producing a circuitcomponent built-in module having a multilayered structure comprising thesteps of: processing a mixture comprising 70 wt % to 95 wt % of aninorganic filler and an uncured thermosetting resin into a first sheethaving a through-hole; filling the through-hole with a thermosettingconductive substance so as to form a second sheet having thethrough-hole filled with the thermosetting conductive substance; forminga wiring pattern on a principal plane of a release film and mounting acircuit component on the wiring pattern; positioning and superimposingthe second sheet on the principal plane of the release film, andpressing the second sheet together with the release film provided withthe circuit component, thereby forming a third sheet in which thecircuit component is buried; peeling the release film from the thirdsheet so as to form a fourth sheet; and positioning and superimposing aplurality of sheets produced in the same manner as the fourth sheet anda film including a wiring pattern portion, and pressing and heating theplurality of sheets and the film including the wiring pattern portion,thereby forming a fifth sheet having a multilayered structure in whichthe thermosetting resin and the conductive substance are cured.
 27. Themethod for producing a circuit component built-in module according toclaim 26, wherein the circuit component comprises an active component,and the conductive substance comprises a conductive resin composition.28. The method for producing a circuit component built-in moduleaccording to claim 26, wherein the film including the wiring patternportion is formed of a copper foil, and the method further comprises astep of removing the copper foil in a portion other than the wiringpattern portion so as to form a wiring pattern, said step of removingthe copper foil is after the step of forming the fifth sheet.
 29. Themethod for producing a circuit component built-in module according toclaim 26, wherein the film including the wiring pattern portion isformed of a release film having a wiring pattern formed on one principalplane thereof, and the method further comprises a step of peeling therelease film from the fifth sheet, said step of peeling the release filmis after a step of forming the fifth sheet.
 30. The method for producinga circuit component built-in module according to claim 26, the methodfurther comprising a step of injecting a sealing resin between thecircuit component and the wiring pattern, said step of injecting asealing resin is after the step of mounting the circuit component on thewiring pattern.
 31. The method for producing a circuit componentbuilt-in module according to claim 26, wherein the thermosetting resinand the conductive substance are heated at 150° C. to 260° C. forcuring.
 32. The method for producing a circuit component built-in moduleaccording to claim 26, wherein the thermosetting resin and theconductive substance are pressed at a pressure of 10 kg/cm² to 200kg/cm² while being heated for curing.
 33. The method for producing acircuit component built-in module according to claim 26, wherein thestep of forming the first sheet further comprises a step of heating thesheet mixture at a temperature below a cure temperature of thethermosetting resin, thereby eliminating adhesion of the sheet mixture,said step of heating the sheet mixture is after the step of forming themixture into the sheet.
 34. The method for producing a circuit componentbuilt-in module according to claim 26, wherein the step of forming thethird sheet by burying the circuit component in the second sheet isperformed at a temperature below a cure temperature of the thermosettingresin.
 35. The method for producing a circuit component built-in moduleaccording to claim 26, wherein the step of mounting the circuitcomponent on the wiring pattern comprises a step of electrically andmechanically connecting the circuit component and the wiring patternwith solder.
 36. The method for producing a circuit component built-inmodule according to claim 27, wherein the step of mounting the activecomponent on the wiring pattern comprises a step of electricallyconnecting a gold bump of the active component and the wiring patternwith a conductive adhesive.